The Marked Goby (Ctenobgobius stigmaticus): A Rare North Carolina Fish Enigma

Abstract

Abstract The marked goby (Ctenogobius stigmaticus Poey, 1860) is a diminutive, uncommon, tropical-subtropical Atlantic fish. It is considered rare in North Carolina. It has been confused in the past with the similar darter goby (Ctenogobius boleosoma Jordan and Gilbert, 1882) and considered common in North Carolina. Recently, some of the confusion has been eliminated and characters to separate these two similar gobies identified. These characters were used to determine that six specimens were collected and cataloged from the state (one is missing, but a photograph has the marked goby coloration). Examining the remaining five, it became obvious that only one is C. stigmaticus. The four others are presumably the darter goby, as anal fin ray counts (which presumably was used to separate them) may overlap. Differences in head shape, maxillary length relative to eye, and the presence of tusks in C. stigmaticus compared to the darter goby could be considered in future keys. Color patterns are also strikingly different in specimens where color still exists. Unfortunately, the four specimens in question lack clear color patterns after preservation. Thus, only two specimens of the marked goby from North Carolina are known. Fortunately, these specimens were captured with substantial environmental data during the most intensive inshore aquatic survey of fishes and macroinvertebrates in the state: daily sampling from March to November 1968–1977 with varied gear in the lower Cape Fear River and adjacent ocean. The range of the marked goby thus extends from SE North Carolina to the border of Brazil and Uruguay, roughly 34 N to 34 S. All specimens have been taken in large lagoons or estuarine bays, in shallow to intertidal waters, on muddy-sand bottoms, and in moderate salinities. The difficulty in sampling these small (≤80 mm TL), slender fishes may also contribute to their scarcity and lack of knowledge.